During the period 1870–1913, Canada had a well-diversified branch banking system while banks in the U.S. unit banking system were less diversified. Canadian banks could issue large-denomination notes with no restrictions on their backing, while all U.S. currency was essentially an obligation of the U.S. government. Also, experience in the two countries with regard to bank failures and banking panics was quite different. A general equilibrium business cycle model with endogenous financial intermediation is constructed that captures these historical Canadian and American monetary and banking arrangements as special cases. The predictions of the model contradict conventional wisdom with regard to the cyclical effects of banking panics. Support for these predictions is found in aggregate annual time series data for Canada and the United States.